Floating piston engines



Dec. 27, 1960 J. JARRET ET AL 2,966,148

FLOATING PISTON ENGINES Filed Dec. 17, 1957 4 SheetsSheet 1 5wrrcHCONTROL Qual- Mia.

Dec. 27, 1960 JARRET Er AL 2,966,148

FLOATING PISTON ENGINES Filed Dec. 1'7, 195'? 4 Sheets-Sheet 2 Dec. 27,1960' J. H. JARRET ETAL 2,966,148

' FLOATING PISTON ENGINES Filed Dec. 17, 1957 4 Sheets-Sheet 3 PuLsE GEN ERATO R.

Dec. 27, 1960 J. H. JARRET ETAL 2,956,148

FLOATING PISTON ENGINES Filed Dec. 17, 1957 4 Sheets-Sheet 4 UnitedStates Patent FLOATING PISTON ENGINES Jacques Henri Jarret, 11 Rue desChenes, Le Vesinet, France, and Jean Marie Baptiste Jarret, 18 Rue duMont-Valerian, Saint-Cloud, France Filed Dec. 17, 1957, Ser. No. 703,428

Claims priority, application France Dec. 18, 1956 7 Claims. (Cl. 123-46)This invention relates to engines of the floating piston type andprovides improved operating means for such engines especially inconnection with starting, regulation, and synchronization between thepistons of such engines. its general object is to provide such meanswhich will fulfill various practical requirements more completely thanthe means heretofore available.

The invention provides an arrangement for use with a floating-pistonengine, which comprises at least one magnetic element rigidly connectedwith a piston of said engine, a magnetic circuit with respect to whichsaid element is movable on reciprocation of the piston to modify thereluctance of said magnetic circuit, and ener gizable electric windingmeans inductively associated with said magnetic circuit and connectedwith an electric circuit, whereby a mutually coupled relationship ispresent between the variations in the kinetic energy of reciprocation ofsaid element and piston, and variations in the electrical energy in saidelectric circuit, so that energy can be selectively transferred fromsaid engine to said electric circuit and vice versa.

The arrangement is operable as a starting device for floating-pistonengines, and in that case one or preferably a series of electric voltagepulses are applied to the electric windings, preferably alternately inone and the other of two windings associated with respective legs of amulti-legged core forming said magnetic circuit, each of said legshaving a gap in which an associated movable magnetic element is movable,both movable elements being coupled for bodily reciprocation with theengine piston and being so associated with said respective legs of themagnetic circuit that the application of said pulses alternately to thetwo related windings will cause a bodily reciprocation of said movableelements and hence the piston coupled thereto, thereby starting theengine.

Where the invention is applied to the feed regulation of the floatingpiston engine, variations in an electrical characteristic of the currentinduced in one or more windings associated with the magnetic circuit maybe used to operate a suitable relay device, such as a solenoid relay,which in turn may produce a mechanical displacement of a regulatorcontrol element such as an air or fuel intake valve. In connection withsuch a regulating system, the arrangement of the invention is able toprovide a servo-loop or feedback action of extremely eflicient andadvantageous character, as will be made apparent from the detaileddisclosure hereinafter.

Where the invention is applied to the synchronization of a pair ofconjugate floating pistons ina common ice cylinder of an engine, eachpiston may have an associated movable magnetic element mechanicallyconnected with it, each element cooperating with a respective magneticcircuit, and means are provided for coupling both circuits insynchronizing relationship. Thus, the winding means associated with therespective magnetic circuits can be cross-connected into a balancedcircuit so that in case of a lack of synchronization between thereciprocation of the two elements, energy will be transferred in one orthe other sense over said balanced circuit to exert magnetic forces onsaid elements which will restore them to accurate synchronism.

Exemplary embodiments will now be described in detail by way ofillustration but not of limitation and with reference to theaccompanying drawings wherein:

Fig. 1 is a diagrammatic sectional view of one embodiment of theinvention which is particularly suitable as a starting device for afree-floating piston engine, the section being taken along the line IIof Fig. 2, as seen in the direction of arrows;

Fig. 2 is a section taken on the line IIII of Fig. 1, as seen in thedirection of arrows;

Fig. 3 is a diagrammatic view of a part of a throttle regulating deviceconstructed in accordance with one embodiment of the invention;

Fig. 4 is a diagrammatic view of an automatic injection regulatingdevice constructed in accordance with another embodiment of theinvention; and

Fig. 5 is a diagrammatic sectional view of a further embodiment of theinvention as applied to the synchrom'zing of a pair of conjugatefloating pistons.

The present invention will first be described with particular referenceto its operation as a starting device as illustrated in Figs. 1 and 2.As there shown the engine comprises a cylinder 1 having a singlefloating piston 6 reciprocable therein but it will be understood that asingle piston is shown only for the purpose of simplifying thedisclosure.

Associated with the cylinder 1 are a spark plug or igniter 2, an intakeport 3 (Fig. 1), an exhaust port 4 (Fig. 2) and a transfer or by-passduct 5. It will be understood that the engine would normally comprisesuch fuel supply equipment as a carburetor or an injector, not shown.

The engine here shown is a two-stroke engine and its piston 6 isaccordingly formed with a transfer or bypass port 7. As ischaracteristic for free-floating piston engines, the piston rod 8 has noconnecting rod coupled with it for the transmission of movement.

Rigidly connected with the free end of piston rod 8 are two of spacednon-magnetic bar members 9a and 9b (Fig. 2) which are rigidlyinterconnected at their ends to form a frame. Secured to the end of saidframe remote from the piston 6 is a device for ensuring a positivereturn of the piston 6 at its outer dead centre position. Such device isconventional and is here shown as comprising a piston 10 reciprocatingin a chamber 21 constituting an auto-compressor device.

The electromagnetic section of the system in the illustrated embodimentcomprises a magnetic circuit in the form of a core having two side legs11a and 11b and a central leg 12, all three legs being interconnected bytransverse end legs 13a and 13b. The central leg 12 is here shown solidbut itwill be understood that the present invention may advantageouslybe combined with a system according to the applicants prior U.S. PatentNo. 2,829,276 wherein an electromagnetic system somewhat similar to thatof the present application is used for converting the reciprocation of afloating piston engine to a rotational movement, and in such case thecore leg 12 may be formed with a cutout for receiving a rotatablearmature of a repulsion type motor therein, the ends of said legdirected towards the armature serving as magnetic pole pieces for therepulsion type motor.

In the embodiment described the side legs 11a and 11b are formed withaligned transverse cutouts which provide relatively wide airgaps 11a,Lib in each side leg, so that such airgaps insert high reluetanees intothe associated branches of'the magnetic circuit,- the increase inreluctance'being at least 100% of its-initial value, and preferablyexceeding said initial value by a factor of about from 5 to 20.

Freely reciproeable together with frame 9a, 9b in said airgaps 11a, 11bwith just enough clearance to avoid friction are two movable magneticelements 14a and 14b which are preferably vane shaped and of suchdimensions in a direction transverse to the legs 11a and 111; as tosubstantially fill the airgaps 11a, 11b'. The spaced vanes 14a and 14bare mounted within the frame formed by the nonmagnetic members, 9a and9b at relative positions such that when one of the vanes is positionedin its airgap in registering relation with the side leg 11a or 11b,respectively the other vane is completely clear of the airgap in theother side leg and is positioned outside the magnetic core.

Wound about the side legs 11a and 11b are the coils or windings 15a,15b, respectively. Depending on the particular use to which the systemis to be put, the windings 15a and 15b are arranged to be energized froma D.-C. source 16 one at a time or to be energized simultaneously fromthe source 16, in series or in parallel. For the purpose of selectivelydisconnecting and connecting the windings 15a, 15b from and to eachother there is provided a jack or another type of coupler deviceschematically indicated at 16c and having its terminals connected withthe source terminals. A double-pole double-throw switch 16d makes itpossible, in the open-circuit condition of the coupler, to selectivelyenergize one or the other of the two windings, as will be readilyunderstood upon observation of the connections shown, which include,lines 162 connecting the source 16 to the coupler and to the switch, andthe lines 16a and 16b connecting the windings 15a and 15b to theopposite switch and coupler, terminals.

In the instant embodiment the windings 15a and 15b are wound with suchpolarities that. they tend to generate, when energized, magnetic fluxesof suitable polarities in the central core leg 12 as will presentlyappear.

The electro-magnetic section now being described, with reference toFigs. 1 and 2 isapplicable, according to the invention, also forpurposes other than the starting of the engine, e.g. for automaticregulation of air and/or fuel supply and for synchronization of thepistons in a twinpiston engine. While the latter applications will bemore specifically described hereinafter with referenceto Figs. 3 to5,'it may be noted at this point that, when the electromagnetic sectionis utilized as a regulator or as a synchronizingmeans, the windings 15aand 15b are wound in such a way as to generate magnetic fluxes ofopposed polarities through the central leg 12. Furthermore,

'for certain applications an additional winding 17 may be provided onthe central leg as will later appear, but tlus winding 17 is not usedwhen the system performs an engine-starting function. a

v The electromagnetic section including the core, and windings thereonis enclosed in a casing 19 and is secured theretoby suitablebolts orcross members 29.

The system described is operated as follows for starting 7 afloating-piston engine. Assuming that. a current p e of suitablepolarity is supplied to one of the windings say 15a, a magnetic flux iscreated in the associated side leg 11a developing an attractive forcewhich causes the movable element 14a to be drawn inwards of its airgap1111:, thereby causing, from the position shown as well as from anextreme left position, a rightward bodily displacement of the rigidassembly including 9a, 9!; piston rod 8, piston 6, and the other coreelement 14b. Thereafter, another current pulse supplied to the winding15b will shift the other element 14b leftward and cause a leftwardbodily displacement: of the assembly including the piston. Hence thedelivery of a current pulse to one of the windings 15a, 15b andpreferably an alternate application of pulses to both windings 15a, 15b,will result in reciprocating the piston 6 in the cylinder therebyproviding a means of starting the engine. Advantageously the rate ofalternate application of voltage pulses to the windings 15a and 15b isinitially slow and is gradually increased while the duration of thepulses may 'be decreased, through any convenient means F capable of e.g.moving the contact arms of change-over switch 16d alternatingly betweenits alternative circuit-closing positions, at a predetermined graduallyincreasing rate thereby providing a highly efficient and reliablestarting action; it will be understood that means (not shown) would beprovided for injecting the fuel and/or igniting the fuelair mixture atthe proper times in correlation with the rate of application of theelectric voltage pulses to the windings.

The timing of application of the pulses to the alternate windings may bedetermined in any of various ways. Thus a simple switch such. as thatshown at 16d may be used, or a device having an equivalent effect.Preferably delay means, not shown, are interposed in the circuits of thewindings and the delay time may be made automatically adjustable toprovide an optimum timing of the alternate pulses, particularly thegradually increasing rate of pulse delivery men-tioned above. The mostsuitable actual duration of time lapse between the pulses and theamplitude thereof would naturally depend on the characteristics of theengine, such as nominal power output and speed and length of pistonstroke. The source 16 may be provided by a storage battery or otherconvenient generator.

We shall now describe an embodiment of our invention as appliedspecifically to the fuel supply regulation of floating-piston engines.The problem here is that of automatically controlling the setting ofsome control such as a, valve, which acts e.g. on the rate of supply ofcombustible mixture to the cylinder or cylinders, in response to someoperating factor of the engine such as the engine speed or load, andthis is accomplished according to the invention by operating saidcontrol in response to varia tions in the electrical energy'put out by apart of the electromagnetic circuit. It is especially advantageous tocombine this application of the present invention with theelectromagnetic drive system of applicants aforementioned patent forconverting the reciprocation of floating pistons into rotary motion,including means for varying the drive ratio.

Whereas in the first embodiment of this invention relating to thestarting of an engine voltagewas alternately supply -to each of twowindings of the system in order to reciprocate the air of magneticelements connected with the engine piston, in the application of theinvention to an engine regulator system use is made of the electricoutput i.e. the amperage, the voltage or the frequency of a currentinduced in a windingof the electromagnetic system in response to thereciprocation of said movable magnetic elements due to the drivingaction of the piston 6 in the two-stroke engine operating in normalmanner. Excitation means must therefore be provided and this may be donein any of various ways. However, in view of the desirability ofcombining this system both with the drive system disclosed in theaforementioned patent and/or with the starting device described hereinwith reference to Figs. 1 and 2, it is convenient to use theafore-mentioned windings 15a, 15b of the system of Figs. 1 and 2 asexcitation windings, said windings in that case being preferably coupledtogether by means of coupler 160. Thus, after first having started theengine with coupler 160 in open-circuit condition, the coupler wouldthen be moved to closed condition (while switch 16d is held open) sothat the same system thereafter performs the regulating function. Inthis case, the jack 16c in closed position connects both windings 15aand 15b in parallel with the source 16 so that the legs 11a and 11b aremagnetized. The alternating movement of the members 14a and 1412 intoand out of the respective gaps 11a and 11b periodically increases anddecreases the magnetic flux in 11a and 11b, respectively, wherebymagnetic pulsations are created in the center leg 12, and consequentlycorresponding electric pulses are induced in the winding 17 surroundingthe leg 12. The result is an alternating current output at the terminals18 and applicable to an electro-mechanical device C referred to belowand controlling the engine intake.

In using the system of the invention to regulate the operation of theengine the fuel or/ and air supply to the engine may be regulated inresponse to any desired electrical characteristic of the outputelectrical energy, including the frequency, voltage, current or phasecondition.

In one form, wherein the frequency of the output energy is used, theengine intake may be regulated in a manner to maintain the reciprocationrate, and hence the mean effective velocity, of the pistonssubstantially constant, while the engine output is allowed to vary overthe full range from zero to a prescribed nominal load. For this purposean air or fuel intake control valve (arranged at D between the device Cand the intake port 3) may be operated at C by way of a conventionalelectromechanical relay device responsive to frequency variations in theoutput voltage, so that any departure of the frequency from a prescribedvalue will result in altering the setting of the valve through saidrelay in such a sense as to return the engine velocity to normal, i.e.increase the fuel supply in case of a drop in piston velocity and outputvoltage frequency, and reduce the supply in case of a rise in pistonvelocity and voltage frequency. The auxiliary electromechanical relaydevice may comprise a conventional sliding-core solenoid device e.g.that of Fig. 4 energized by way of a frequency sensitive circuit whichmay contain a conventional discriminator capable of varying its outputvoltage in response to frequency variations.

In another form of regulating system according to the invention theengine intake is varied in such a manner as to maintain the output ofthe engine constant under varying load. In such a type of system theremay be provided in addition to the energizing or primary winding orwindings 15a and 1512, one or more secondary windings, in which acurrent is induced which will vary as a function of the load because achange in load will change the speed and frequency of the piston 6. Thesecondary Winding may constitute the winding 17 shown in Fig. l and theelectromagnetic system will then operate somewhat in the manner of astatic alternator producing an A.-C. output across the pair of terminals18 (Fig. 1). Alternatively, the secondary winding means may comprise thewinding of a rotor operated as an electric motor in the manner disclosedin our US. Patent No. 2,829,276. In any case the varying voltage fromthe secondary winding 17 may be used to energize a slidingcore solenoidrelay device of the type above referred to for operating an intake valveor other control as described above.

In yet a third form of the regulating aspect of the invention mattersmay be so arranged that the engine velocity increases slightly withincrease in load. For

this purpose the fuel supply to the engine may be controlled e.g. by anelectro-mechanical device as shown in Fig. 4 in response to a voltagewhich is held substantially constant within a predetermind narrow range,as induced in an auxiliary winding similar to winding 17 of Fig. 1, butin this case the voltage induced therein is according to establishedlaws governing the generation of alternating voltage proportional bothto the reciprocation frequency of the magnetic cores 1411-1412 and tothe magnetic flux in the magnetic circuit. Thus, when said flux changessimultaneously with a change in the load, the reciprocation frequency ischanged inversely so as to maintain the voltage in said auxiliarywinding substantially constant.

The approximately constant voltage delivered by the auxiliary Windingcan, additionally, be used for such purposes as to charge a storagebattery which, incidentally, may serve as the D.-C. source in a systemaccording to the invention, such as source 16 of Fig. 1.

Figs. 3 and 4 schematically illustrate two exemplary embodiments of theelectro-mechanical portion of a regulating system according to thelast-mentioned form of the invention, i.e. that wherein a substantiallyconstant voltage is put out by an auxiliary winding such as, orequivalent to, the winding 17 in Fig. 1. Referring first to Fig. 3, athrottle valve 21 is shown in a carburetor air intake conduit 22 whichforms part of a fuel supply circuit for a floating-piston engine, notshown. Valve 21 is connected by way of pivotal linkage 27-26 with thesliding magnetic core 25 of a solenoid device having a housing 24 andwinding supply terminals 23. The core 25 has a flange 29 which is biasedinto engagement with an abutment member 36 when the valve 21 is infullyopen position by the action of a spring 28 so calibrated that thecore is maintained in its left-hand position of abutment with the member36 as long as the voltage applied to the solenoid terminals 23 does notexceed a prescribed value. The solenoid terminals 23 are con nected tothe output terminals 18a of an electromagnetic system which may besimilar to that shown in Fig. 1, in which case the terminals 18a wouldbe identical with the terminals 1% shown in that figure as providing theoutput from auxiliary winding 17. Should the voltage output from Winding17 exceed the prescribed value the solenoid core 25 is moved rightwardof Fig. 3 thereby partly closing the throttle and reducing the enginespeed by such an amount that the voltage across the terminals 18a isrestored to the prescribed range.

Referring to Fig. 4, the regulating system is shown as applied to a fuelinjector for a floating-piston engine of the direct injection type. Theinjector assembly is positioned in the wall 1b of the engine cylinder.in jector chamber 31 is maintained filled with fuel under pressure butthe fuel is prevented from flowing out of the chamber into the cylinderthrough an injection orifice 33 by means of a needle valve member 32normally sealing the inner end of said orifice. The valve member 32 canbe lifted off its seat to a variable extent by the action of anelectromagnet 34 acting on a magnetic armature secured to the rear endof valve member 32. The winding of electromagnet 34 is energized withvolttage pulses delivered from a suitable variable pulse gen erator 35,which maybe of any appropriate electronic type e.g. a conventionalmonostable or one-shot multivibrator, operated to generate a voltagepulse of predetermined duration upon being triggered by the individualpulses delivered via 18 at each reciprocation of the engine. The inputterminals of the variable pulse generator 35 are connected to theterminals 18 which may be the terminals 18 of Fig. l, and the generatoris so constructed that when the voltage applied to it from terminals 18exceeds a prescribed value, the duration of the generated pulses iscorrespondingly reduced. Such a generator is well-known to those versedin this art and has been described by Jean-Marie Moulon in his book Les7 systems.

900,016. The periods during which the injection valve 32 is open arereduced accordingly and so is the rate of fuel supply to the engine. Theengine operates at a slower rate until the voltage across terminals 18has been restored to its prescribed range.

It will be understood that in the general showing of Fig. l the block Cmay indicate any intermediate electromechanical relay device such as thesolenoid device of Fig. 3 or that of Fig. 4, which relay device in turncontrols the operation of the engine as indicated by the connection D inFig. 1.

An embodiment of the invention will now be described in its applicationto the synchronization of a pair of floating pistons. In its preferredform a floating-piston engine comprises one or more cylinders eachcontaining a pair of svmmetrically operating pistons reciprocating inopposition to each other, and which may be termed conjugate pistons. Inoperation the desired accurate opposition between the reciorocations ofthe two coniugate pistons tends to be disturbed by various factors whichintroduce phase displacements between the'respective operating cyclesand the correct operation of the engine requires the provision of somesynchronizing means for maintaining the desired opposed relationshipbetween the pistons at all times. Conventional synchronization systemsfor floating-piston engines have generally been mechanical in character,involving the provision of symmetrical linkages connected with therespective pistons and with each other by way of a suitable kinematictransmission. In operation, the linkages are subjected to very highaccelerations and consequent stresses, and limit to the operating speedsachievable with engines of this type. Moreover such linkages aregenerally objectionable in that they destroy the truly free-floatingcharacteristic which constitutes the fundamental advantage of suchengines.

Other known types of synchronizing systems for floating-piston enginesare pneumatical rather than mechanical and operate by way of the usualair cushions normally present in such engines. Such pneumaticsynchronizing systems can be controlled electrically or mechanically.

In the systems of the present invention synchronism is achieved betweenthe operation of coniugate pistons in a floating-piston engine byassociating with each piston one or more movable magnetic elements suchas 14a and 14b of Figs. 1 and 2, cooperating with a pair ofelectromagnetic systems each of which may be of the same generalcharacter as shown in those figures which systems are so coupled witheach other (electrically or magnetically) that, in case of a disturbancein the synchronism (or a phase displacement) between the reciprocationsof the two magnetic elements (or sets thereof), electromagnetic forcesare set up which act upon said elements to restore them to synchronism.

The electromagnetic systems associated with the two pistons arepreferably coupled together electrically to' cause an interchange ofelectric power between the two systems in the event that thereciprocations of the magnetic elementsthereof tend to fall out of step,so that power is transferred from one to the other of the systerns andapplies to one or each magnetic element a force acting to restore itinto synchronism with the other element. For this purpose, the circuitsof windings such as 15a and 15b in Fig, 1 may be connected in oppositionto provide a balanced circuit, 'e.g. by connecting the midpoints of therespective windings, or/and by connecting the ends of both windings inparallel across a further winding provided on the third arms of bothelectromagnetic Fig. '5 illnstrates'suclran embodiment" of the inventionwherein a cylinder 36 has two floating pistons 37 and 38 reciprocatingtherein, and normally adapted to be positioned in opposition to eachother on either side of the transverse midplane EE' of the cylinder. Thecylinder is shown as including a pair of intake ports 39 and a pair oftransfer or bypass conduits 40. The exhaust ports lie outside the planeof and hence cannot be seen in Fig. 5. Secured to the pistons 37 and 38are rigid transmission rods 41 and .42, respectively, which serve todrive a load mechanism, not shown, such as a compressor or converter ofmechanical energy. The load mechanism forms no part of the presentinvention and is not illustrated but can be assumed to be interposed inthe broken sections 41a and 42a shown in each of the transmission rods41 and 42.

Each transmission rod further has connected with it an air-cushioningdevice, of the general type shown as 10, 21 in Fig. 1, and serving toprovide for a smooth reversal of movement of the pistons at each outerdead center position. Said air cushioning devices are here shown ascomprising pistons 45 and 46, respectively secured on the ends of rods41 and 42 and operating in cylinders 42 and 44, respectively.

Each transmission rod 41, 42 carries intermediate its length a magneticsection 47, 48, respectively, each cooperating with an electromagneticassembly of a construction somewhat different from that shown in Fig. 1.The two assemblies being identical only the left hand one of the twoshown in Fig. 5 will be described, the components of the other systembeing designated with the same reference numerals followed by sutfix 11instead of a.

Said electromagnetic assembly comprises a three-legged magnetic corehaving the side legs 49a and 51a and a center leg 50a, all enclosed in acasing 61a. The median portions of legs 49a and 59a are formed withcutouts to provide Wide airgaps within which the magnetic element 47secured to the piston 37 is reciprocable. The leg 51a is not formed witha cutout and it will be noted that in case the said third leg 51a ispositioned in the longitudinal center plane of the system asillustrated, the piston rods 41 and 42 would have to include two prongedsections surrounding said third legs 51a and 51b, respectively, in orderto permit unimpeded reciprocation. The side leg 49a carries anenergizing winding 53a (which may include one or more separate windingsections), and the leg 50a carries a winding 52a. Windings 52a andwindings 53a are connected in series relation and with a D.-C. source544': by leads 55a and 56a. While separate D.- C. sources 54a and 54bare shown, a common source should preferably be used.

The windings 52a and 53a are wound and connected in such a way that theytend to create magnetic fluxes of reverse sign in the third core leg51a. In view of the cyclic variations in reluctance produced in legs 49aand 59:: by the reciprocation of the element 47, an alternating magneticflux is generated in the third, fixed-reluctance leg 51a, since theresultant flux in the latter corresponds to the algebraic sum ofthefluxes generated by the two windings.

Furthermore, as a result of'the cyclic variation in reluctance in thelegs 49a and 50a electromotive forces are induced in the windings 52aand 53a. It will be readily understood that if the electromagneticsystem associated with the right-hand piston 38 accurately presentscharacteristics similar to those of the system associated with theleft-hand piston, then by providing cross connections between one ormore symmetrically disposed points of the two circuits associated withthe respective systems there willbe obtained a balanced output circuitin which no current will flow as long as the reciprocations of themovable magnetic elements 47 and 48 are efiected in. strict phaseopposition with one another, but there will be current flow in one orthe other sense over said cross connections should a phase displacementoccur between the reciprocation of the two elements;

Electrical energy is thus transferred from that system in which themovable element is in leading relationship to the system in which themovable element is lagging, and the electrical energy thus transferredgenerates a magnetic force which imparts to the lagging element 47 or 48the requisite surplus of kinetic energy for bringing it back intosynchronous relationship with the other element. The force thus actingto restore synchronism between the two movable elements and hence thepistons respectively connected thereto, increases at a very rapid ratewith the degree of phase displacement between the two elements. Thus,the differential voltage appearing across the ends of the synchronizingconnection such as 57 in Fig. 5, for a linear phase displacement betweenelements 47 and .3 as low as A the reciprocation amplitude of eachelement, can be many times the value of the excitation voltage appliedat 54a and 54b. Moreover it will be noted that the large forces thusdeveloped are axial forces applied exclusively to the simple, ruggedmagnetic elements 47 and 48 solidly connected and with the pistons,rather than being applied to complex pivotal linkages as in conventionalmechanical synchronizing devices.

The cross connection or connections between the two symmetrical circuitscan be variously arranged to provide the balanced synchronizing circuit,a simple arrangement being that wherein the synchronizing crossconnection 57 connects the midpoints between the pairs of windings52a-53a and 52b-53b, as shown in Fig. 5 alternatively, a balancedsynchronizing circuit may be obtained by providing on each coreadditional windings such as the windings 58a, 58b shown encircling thethird core legs 51a and 5112 respectively, and by connecting suchwindings in parallel as shown by the connections 59 and 60. While theresulting circuit might be used for the purpose of synchronization justdescribed, it is here shown as serving to provide an additional outputat terminals 18a which may be used for regulating purposes in a mannergenerally similar to that described in connection with the otherembodiments.

It will be seen that the invention provides highly advantageousarrangements for the operation and regulation of engines of thefloating-piston type, particularly with respect to the starting,supply-regulation and synchronization of such engines. The regulationprovided by the invention is of a very accurate and flexible character,has a low response time, and is especially advantageous in connectionwith floating-piston type engine since in such engines the reciprocatoryoperation does not tend to be regularized by associated mechanicalcouplings such as connecting rods and crankshafts as in conventionalreciprocating engines. The synchronizing function provided by theinvention also is more advantageous than the means heretofore providedfor a similar purpose. A further advantage of the invention is thefacility with which the various arrangements thereof can be combinedwith one another, as mentioned at various points throughout thespecification, and also combined with the applicants priorelectromagnetic systems such as the variabledrive movements-conversionsystems for floating-piston engines described in applicants US. PatentNo. 2,829,276 already referred to.

As mentioned hereinabove the illustrated embodiment should not beconstrued as restricting the invention since various modifications maybe made in the constructions illustrated and also in the applications explicitly mentioned, without departing from the scope of the invention.Thus, among the many possible structural modifications, it shouldespecially be noted that the magnetic circuit means may assume a varietyof forms other than that of a three-legged (or El-type) core.Multilegged cores are well known in the art, e.g. in magnetictransformers, and are known to admit of a very wide range of variationsin shape and in the disposition and connection of windings thereon, andsimilar variations 10 will be readily conceivable regarding the magneticsystems utilized in the invention. the airgaps in the core in which themovable magnetic element or elements is or are slidable can also bevaried. For example, the solid core legs 51a and 51b in the embodimentof Fig. 5 may be arranged outside the plane of the other legs of thecore (i.e. outside the plane of Fig. 5) thereby reducing the length ofthe magnetic systems in directions parallel with the directions in whichthe pistons reciprocate.

What we claim is:

1. In combination with a floating-piston engine having a cylinder and apiston therein, means defining a magnetic circuit, a magnetic elementsecured to said piston and cooperating with said magnetic circuit forcyclically varying the reluctance thereof on reciproation of the piston,winding means inductively associated with said magnetic circuit, anelectric output circuit connected to said winding means for providing avariable output in response to variations in the reciprocation of saidpiston, and means for feeding back said variable output to said enginefor regulating the operation thereof.

2. In combination with a floating-piston engine having a cylinder and apiston therein, means defining a magnetic circuit, a magnetic elementsecured to said piston and cooperating with said magnetic circuit forcyclically varying the reluctance thereof on reciprocation of thepiston, winding means inductively associated with said magnetic circuit,an electric output circuit connected to the Winding means for providinga variable output in response to variations in the reciprocation rate ofsaid piston, an adjustable feed regulating member for said engine, andmeans connected with said output circuit and said regulating member andresponsive to said variations in output for adjusting said member.

3. The combination claimed in claim 2, wherein said regulating membercomprises a settable valve, and said output responsive means compriseelectromagnetic winding means connected to said output circuit and aspring biased armature positionable by said electromagnetic windingmeans in response to said output variations and mechanically connectedto said valve.

4. The combination claimed in claim 2, wherein said regulating membercomprises an intermittently operable injector valve member,electromagnet means associated with said member and energizable withvoltage pulses for intermittently operating said member, a variablepulse generator connected for energizing said electromagnet means, andmeans connecting said pulse generator to said output circuit for varyingthe duration and timing of said pulses.

5. The combination claimed in claim 2, wherein said responsive means isresponsive to the frequency of said output, and including means forconverting variations in said frequency into regulating displacements ofsaid member.

6. In combination with a floating-piston engine having a cylinder and apair of opposed conjugate pistons IEClPI'O cable therein, means definingsimilar magnetic circuits associated with the respective pistons,magnetic elements secured to the respective pistons and cooperating withthe respective magnetic circuits for cyclically varying the reluctancethereof, energizing winding means inductively associated with saidrespective magnetic circuits, and means connecting the respectivewindings in a balanced electric circuit, whereby a lack of synchronismin the reciprocation of both conjugate pistons will result in a flow ofcurrent over said balanced circuit and a consequent transfer of energyfrom one magnetic element to the other effective to restore saidsynchronism.

7. In combination with an engine of the type described having a cylinderand a piston reciprocable therein, a multi-legged magnetic core havingspaced legs each formed with a gap therein, magnetic elements secured tothe piston for reciprocation therewith and adapted to The arrangement ofst bstantially fill respective ones of said gaps in respective. a d pqion of the p ston, windings sp i y ssociated with said legs adapted whenenergized to generate magnetic forces tending to displace said elementsinto and u of sa d at d gap nd l ctr c ean or en: ergizing said windingsin timed relationship to cause a. reciprocation of said elements andpiston for starting the in said. lect i mea inclu g mea s or app yvoltage pulses to said windings in a timed sequence, and means forcontrolling the timing of said applied pulses to provide an increasinglyrapid reciprocation of said e emen s. duri an ng -sta in operation-References Cited in the, tile of this patent UNITED STATES PATENTSNoacket a1. Dec. 16,

Norton fl v n Nov. 16,

Turner Aug. 11,

, Colgate Sept. 15,

FOREIGN PATENTS France June 9,

France Sept. 29,

